The present invention relates to a device for calculating a cruising range of a vehicle and a method therefor.
FIG. 1 shows a conventional cruising range calculation device (hereafter range calculator). In the figure, reference numeral 1 denotes a fuel tank which stores fuel, 2 is a fuel meter which measures a stored amount of fuel F in the fuel tank 1, 3 is an A/D converter, 4 is an operational distance calculator which measures an operational distance M by counting vehicle speed pulses P, 5 is a calculator which calculates a fuel economy Fm by dividing an operational distance M calculated by the operational distance calculator 4 by a fuel consumption amount Q and which calculates a range K by multiplying a fuel amount F measured by the fuel meter 2 by the fuel economy Fm, 6 is a display which displays a range K calculated by the calculator 5.
Then operation of the device will be described below.
Firstly the fuel meter 2 calculates a fuel amount F in the fuel tank 1 in real time and outputs a measurement result to the A/D converter 3.
On receipt of the measurement result from the fuel meter 2, the A/D converter 3 A/D converts the signal and outputs a measurement result to the calculator 5.
Alternatively, the operational distance calculator 4 counts the number of vehicle speed pulses P output by the vehicle after running a fixed distance, multiplies the count number C by a fixed distance D in a sampling period and calculates an operational distance M of the vehicle.
Operational distance M=count number C of vehicle speed pulse Pxc3x97fixed distance D
The calculator 5 monitors the fuel amount F in the fuel tank 1 based on the measurement result output from the A/D converter 3 and calculates a fuel consumption Q in a sampling period.
fuel consumption Q=fuel amount at initiation of sampling periodxe2x88x92fuel amount at termination of sampling period
The calculator 5 calculates a fuel consumption Q in the sampling period and then calculates a fuel economy Fm by dividing the operational distance M measured by the operational distance calculator 4 by the fuel consumption Q.
fuel economy=operational distance M÷fuel consumption Q
The calculator 5 calculates the fuel economy Fm in the sampling period and then calculates a range K by multiplying the fuel amount F and the fuel economy Fm.
range K=fuel amount Fxc3x97fuel economy Fm
In such a way, when the calculator 5 has calculated a range K, the display 6 displays the range K on an indicator for example.
Apart from the conventional example above, a technique of detecting refueling from the difference between a fuel injection amount supplied to an engine and a stored amount of fuel in a fuel tank is disclosed in JP-A-58-2709.
Since the range calculator is constructed as above, it is possible to accurately calculate a range of a vehicle with a high accuracy measurement by the fuel meter 2. However since the surface of the fuel in the fuel tank 1 develops a movement when the vehicle is running, the accuracy of the measurements of the fuel meter 2 deteriorates. Thus the problem has arisen that it is not possible to accurately measure a range of the vehicle.
The present invention is proposed to solve the above problem and has as its object the provision of a device for calculating a cruising range of a vehicle and a method therefor which can calculate a range of a vehicle with high accuracy even when the surface of liquid fuel in a fuel tank is moving.
The device for calculating a cruising range of the present invention calculates a remaining amount of fuel by subtracting an injected amount of fuel measured by a fuel injection measuring means from a fuel amount measured by said fuel measuring means and which calculates a fuel economy by dividing a running distance measured by said operational distance measuring means by a fuel injection amount.
In this way, even when a movement is generated on the surface of the fuel in the fuel tank, it is possible to accurately calculate a vehicle cruising distance as it is possible to accurately calculate a fuel economy and a remaining fuel in the fuel tank.
The device for calculating a cruising range of the present invention calculates a stored fuel amount in the fuel tank, and then calculates the difference of the remaining fuel calculated by the remaining fuel calculation means and the stored fuel amount. When the difference is greater than a standard value, the fact that refueling is performed in the fuel tank is communicated to the fuel measuring means.
In such a way, even when a movement is generated in the surface of the fuel in the fuel tank, it is possible to detect the supplied amount of fuel accurately.
The device for calculating a cruising range of the present invention measures an inclination of the vehicle and corrects the standard value on the basis of the inclination.
In this way, it is possible to accurately detect refueling even when the surface of the fuel is inclined in the fuel tank when the vehicle is stopped on a sloping road.
The device for calculating a cruising range of the present invention measures a fuel amount when a fixed time has elapsed after the vehicle has stopped.
In this way, it is possible to measure the amount of fuel after the movement of the fuel surface has stabilized. As a result, it is possible to measure the amount of fuel accurately.
The device for calculating a cruising range of the present invention executes the measurement of the fuel amount on a plural number of occasions and thus enables use of an average value of the measurement results as a final measurement value.
In this way, even when a movement in the surface of the fuel is generated, the influence of the movement is reduced and the measurement accuracy of the fuel amount is improved.
The device for calculating a cruising range of the present invention is adapted to detect the category of road currently traveled and to calculate a fuel economy when the category of road varies.
In this way, it is possible to calculate a fuel economy accurately even when the category of road currently traveled varies.
The device for calculating a cruising range of the present invention is adapted to measure a fuel amount in a fuel tank when the vehicle is stationary.
In this way, even when refueling is not performed, it is possible to remeasure the fuel in the fuel tank and as a result it is possible to improve the measurement accuracy of the remaining fuel.
The device for calculating a cruising range of the present invention measures a fuel injection amount supplied to the engine and multiplies a fuel amount measured by the fuel measuring means by the fuel injection amount. Then the result of the multiplication is divided by the remaining fuel calculated by the remaining fuel calculation means and the injection amount is corrected.
In this way, it is possible to suppress rapid variation in the cruising range by suppressing rapid variation in the injection amount.
The device for calculating a cruising range of the present invention is adapted to acquire fuel injection amount through a maintenance communication line from a fuel measurement means.
In this way, it is possible to acquire a fuel injection amount from the fuel measurement means without the need for a new maintenance communication line in the vehicle.
The device for calculating a cruising range of the present invention is adapted to acquire fuel injection amount from a fuel measurement means only when a self-diagnosing tester is not connected to the maintenance communication line.
In this way, when a self-diagnosing tester is connected to the maintenance communication line, it is possible to avoid any impediment to the processing of the self-diagnosing tester.
The method for calculating a cruising range of the present invention is adapted to calculate a remaining fuel amount by subtracting a fuel injection amount supplied to the engine from the fuel stored in the fuel tank, to calculate fuel economy by dividing the vehicle running distance by the fuel injection amount supplied to the engine and to calculate a cruising distance by multiplying the remaining fuel by the fuel economy.
In this way, even when the surface of the fuel in the fuel tank is moving, it is possible to accurately measure a fuel economy and remaining fuel amount in the fuel tank. As a result, it is possible to measure a vehicle cruising distance accurately.
The method for calculating a cruising range of the present invention is adapted to measure stored fuel in the fuel tank and to calculate the difference of stored fuel and remaining fuel. When the difference is greater than a standard value, the device is adapted to detect that fuel supplied to the fuel tank.
In this way, even when the surface of the fuel in the fuel tank is moving, it is possible to accurately detect the supplied amount of fuel.
The method for calculating a cruising range of the present invention is adapted to measure an inclination of the vehicle, and to correct the standard value depending on the inclination.
In this way, even when an inclination is generated in the surface of fuel in the fuel tank when the vehicle is stationary on an incline, it is possible to accurately detect refueling.
The method for calculating a cruising range of the present invention is adapted to a stored amount of fuel after a fixed period has elapsed after the vehicle has stopped.
In this way, after the movement of the fuel surface has decreased, it is possible to measure the stored fuel and as a result, to accurately measure the stored fuel.
The method for calculating a cruising range of the present invention is adapted to execute measurement of stored fuel a plurality of times and to use an average value of the measurement result as a final measurement value.
In this way, even when a movement in the fuel surface is generated, the influence of the movement is reduced and the measurement accuracy of the stored fuel is improved as a result.
The method for calculating a cruising range of the present invention is adapted to detect different road types during running and to calculate a fuel economy when the road type varies.
In this way, even when a road type varies, it is possible to calculate a fuel economy with high accuracy.
The method for calculating a cruising range of the present invention is adapted to measure stored fuel in a fuel tank when the vehicle is stationary.
In this way, even when refueling is not performed, it is possible to remeasure stored fuel in the fuel tank and as a result, to improve the calculation accuracy of the remaining fuel.
The method for calculating a cruising range of the present invention is adapted to measure a fuel injection amount supplied to the engine, to multiply the stored fuel in the fuel tank with the injected amount, to divide the calculation result by the remaining fuel and to correct the injection amount.
In this way, it is possible to suppress rapid variations in the cruising distance by suppressing rapid variations in fuel injection amount.
The method for calculating a cruising range of the present invention is adapted to acquire a fuel injection amount through a maintenance communication line from an engine computer which controls the engine.
In this way, it is possible to acquire a fuel injection amount from an engine computer without the need to provide a new maintenance communication line in the vehicle.
The method for calculating a cruising range of the present invention is adapted to acquire a fuel injection amount from an engine computer only when a self-diagnosing tester is not connected to the maintenance communication line.
In this way, when a self-diagnosing tester is connected, it is possible to avoid any impediment to the processing of the self-diagnosing tester.